Sumsung Plasma Tv PN50A550 dead

[ivtec]

Hguys;i have here a Samsung Plasma Tv PN50A550 Power supply that has a blown main fuse and a huge black spot around the 2 moves resistors ,here some pics,before anything of do you guys think of it,this tv belongs to my friend and i advised him to bring the power supply only because tv is so heavy and since it was completely dead,i assumed it was the power supply issue,any thoughts thanks?

[Dumah Brazorf]

Re: Sumsung Plasma Tv PN50A550 dead

It's dust or sawdust?
Traces seems big in that area so I think you can repair the damaged ones easily.
Those resistor are inrush limiting current ones so probably there's a short after them. Check the main bridge rectifier.

[ivtec]

Re: Sumsung Plasma Tv PN50A550 dead

It's dust or sawdust?
Traces seems big in that area so I think you can repair the damaged ones easily.
Those resistor are inrush limiting current ones so probably there's a short after them. Check the main bridge rectifier.

Thanks Dumah; the 2 bridge rectifiers seem to be ok at least when checked with the diode function,the 2 diodes next to the limiting resistor are ok too,one of the limiting resistors is cracked in pieces the other seems to be intact,when i repair the traces and replace the limiting resistors and the fuse can i connect the power supply to power without being connected to the tv?thanks

[Dumah Brazorf]

Re: Sumsung Plasma Tv PN50A550 dead

Check for short after the bridge rectifier, expecially mosfets.

[ivtec]

Re: Sumsung Plasma Tv PN50A550 dead

Check for short after the bridge rectifier, expecially mosfets.

Thanks Dumah; i checked all these components on the heat sink 20N60C3 and the diode and all show short in circuit,tomorrow i will take them out and see if they are ok, but i think these are short.


do you know if this sumsung kit has those components included ? 20N60C3


http://www.shopjimmy.com/samsung-bn4...repair-kit.htm

[R_J]

Re: Sumsung Plasma Tv PN50A550 dead

Its a very good chance that the contacts are bad in RLYE801 relay. The relay should short out the thermistors when the tv is running, if the contacts are bad all the current is drawn through the thermistors and they burn up.
If you don't find any shorted parts elseware, replace the mov's and the relay and it should work
I think they are SCK-801's
With the thermistors open you won't get any standby voltage if I remember
Also check FB801 fuse, if its good I suspect the standby circuit is o.k.

[ivtec]

Re: Sumsung Plasma Tv PN50A550 dead

Its a very good chance that the contacts are bad in RLYE801 relay. The relay should short out the thermistors when the tv is running, if the contacts are bad all the current is drawn through the thermistors and they burn up.
If you don't find any shorted parts elseware, replace the mov's and the relay and it should work
I think they are SCK-801's
With the thermistors open you won't get any standby voltage if I remember
Also check FB801 fuse, if its good I suspect the standby circuit is o.k.

So far components checked bad out of circuit are, 2 mosfets 20N60C3 and Fuse FB801,
2 Sck 0512 inrush resistors, also i checked ordering these parts from different sources will cost about 40 bucks including shipment and not sure thing cause it maybe something else bad, i checked this power supply the cheapest i could find about 45 bucks,don't know ! what do you think?


http://www.buyqual.com/samsung-bn44-...8aAsolEALw_wcB

[R_J]

Re: Sumsung Plasma Tv PN50A550 dead

If it is "FB 801" that is open, then UB801 standby ic likely bad, shorted. FE 801 is the main fuse off the a/c line. I don't where the 2 mosfets you mentioned are on the board, I don't have this schematic, I'm going by SJ pictures of the board. $45.00 is not a bad price, if you add up the parts you need to repair this one it mmight be cheaper to just replace it.

[ReeceyBurger123]

Re: Sumsung Plasma Tv PN50A550 dead

Main fets short on these vtec kicked in yet

[ivtec]

Re: Sumsung Plasma Tv PN50A550 dead

Well thanks guys,talked to this tv owner and he doesn't want to spend that kind of money on this plasma,i guess he's going to send it to the dumpster,i don't blame him,i wouldn't ,thanks to you all for trying to help., appreciate it.

[freakaftr8]

Re: Sumsung Plasma Tv PN50A550 dead

Even if you did get it repaired it is an A series so be looking for vertical lines or horizontal lines in the screen as it starts to burn away